AVC - Kaspersky Virus Database is a file extension that is mainly used by Kasperskly Lab’s Anti Virus program. It definitely comes in handy when you need it to. This extension is great for storing antivirus definitions for the program. It is also great for downloading protection information which keeps the software up to date as well. There are also AVC files that are named with a three letter prefix. You can update anytime you wish. You will be able to access this download by going online. It is really worth it if you want to keep your system up to date.